Keys are items used to progress though levels in the series. They float alongside the player, much like Bombs and Mining Picks. While their appearance changes slightly throughout the games, they are usually golden with three half-circles in their handles.
When encountering a locked gate, the Skylander must find a key to open it. The key is often nearby but can be hidden or part of a puzzle. In most games, the Skylander can carry as many keys as he or she needs, but most gates are locked with three locks at most. When a key is used on a lock, both the key and the lock disappear.
Specific optional areas force keys to disappear when Skylanders enter them, but the keys are returned to the Skylander when they leave. This usually occurs with puzzles found behind Elemental Gates; if the puzzles involve keys, they usually disappear if they are not used when the Skylander leaves, preventing the player from using them on gates that advance the level.
In most cases, such as in Skylanders: Giants, locks are not specific to keys, which means that any key can open any lock. If this is the case, clever players can use exploits and glitches to carry keys past their intended gates to open gates that are encountered later, skipping major sections of levels.